Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2012

Earnings Per Share (Tables) [Abstract]

Computation of basic and diluted earnings per share

		Year Ended December 31,
		2012		2011		2010
Numerator for basic and diluted earnings
	per share - net income attributable to
	common stockholders	$	221,884	$	157,108	$	106,882
Denominator for basic earnings per
	share: weighted-average shares		224,343		173,741		127,656
Effect of dilutive securities:
	Employee stock options		231		176		125
	Non-vested restricted shares		312		246		420
	Convertible senior unsecured notes		1,067		238		7
Dilutive potential common shares			1,610		660		552
Denominator for diluted earnings per
	share: adjusted-weighted average shares		225,953		174,401		128,208
Basic earnings per share		$	0.99	$	0.90	$	0.84
Diluted earnings per share		$	0.98	$	0.90	$	0.83